U.S. patent application number 11/783972 was filed with the patent office on 2007-08-23 for fuel cell and manufacturing method of the fuel cell.
This patent application is currently assigned to NOK CORPORATION. Invention is credited to Tomohiro Inoue, Yoshihiro Kurano, Yuichi Kuroki, Yasuji Ogami, Atsushi Oma, Kazuo Saito.
Application Number | 20070196717 11/783972 |
Document ID | / |
Family ID | 18973722 |
Filed Date | 2007-08-23 |
United States Patent
Application |
20070196717 |
Kind Code |
A1 |
Kuroki; Yuichi ; et
al. |
August 23, 2007 |
Fuel cell and manufacturing method of the fuel cell
Abstract
In order to prevent an electrolyte membrane from being broken,
and make an assembling steps of a cell easy, in a fuel cell
provided with a membrane electrode complex in which catalyst layers
are respectively arranged on both surfaces of a electrolyte
membrane, first and second gas diffusion layers which are arranged
on both surfaces of the electrode complex, separators for
respectively supplying reaction gas to the first and second gas
diffusion layers, and a gasket for sealing the reaction gas, the
gasket is formed on a surface of the gas diffusion layer so as to
oppose to the separator, at least the gasket forming portion of the
gas diffusion layer has a lower void content than the portion in
contact with the catalyst layer, and the gasket arranged in the
first and second gas diffusion layers is integrally formed at least
via a through hole passing through the first and second gas
diffusion layers.
Inventors: |
Kuroki; Yuichi;
(Fujisawa-shi, JP) ; Kurano; Yoshihiro;
(Fujisawa-shi, JP) ; Inoue; Tomohiro;
(Fujisawa-shi, JP) ; Oma; Atsushi; (Yokohama-shi,
JP) ; Ogami; Yasuji; (Yokohama-shi, JP) ;
Saito; Kazuo; (Fujisawa-shi, JP) |
Correspondence
Address: |
JACOBSON HOLMAN PLLC
400 SEVENTH STREET N.W.
SUITE 600
WASHINGTON
DC
20004
US
|
Assignee: |
NOK CORPORATION
KABUSHIKI KAISHA TOSHIBA
|
Family ID: |
18973722 |
Appl. No.: |
11/783972 |
Filed: |
April 13, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10474520 |
Oct 23, 2003 |
7226686 |
|
|
PCT/JP02/04038 |
Apr 23, 2002 |
|
|
|
11783972 |
Apr 13, 2007 |
|
|
|
Current U.S.
Class: |
429/480 ;
429/483; 429/510; 429/535 |
Current CPC
Class: |
H01M 8/0247 20130101;
H01M 2008/1095 20130101; H01M 8/0271 20130101; H01M 8/0273
20130101; Y02P 70/50 20151101; H01M 8/0286 20130101; H01M 8/0284
20130101; Y02E 60/50 20130101; H01M 8/023 20130101; H01M 8/0276
20130101 |
Class at
Publication: |
429/035 ;
429/044; 429/030; 429/036 |
International
Class: |
H01M 2/08 20060101
H01M002/08; H01M 4/94 20060101 H01M004/94; H01M 8/10 20060101
H01M008/10; H01M 8/02 20060101 H01M008/02 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 23, 2001 |
JP |
2001-124317 |
Claims
1. A fuel cell comprising: a membrane electrode complex in which
catalyst layers are respectively arranged on both surfaces of a
electrolyte membrane; first and second gas diffusion layers which
are arranged on both surfaces of the electrode complex; separators
for respectively supplying reaction gas to the first and second gas
diffusion layers; and a gasket for sealing the reaction gas,
wherein the gasket is formed on a surface of the gas diffusion
layer so as to oppose to the separator, at least the gasket forming
portion of the gas diffusion layer has a lower void content than
the portion which is in contact with the catalyst layer, and the
gasket arranged in the first and second gas diffusion layers is
integrally formed at least via a through hole passing through both
the first and second gas diffusion layers.
2. A fuel cell comprising: a membrane electrode complex in which
catalyst layers are respectively arranged on both surfaces of a
electrolyte membrane; first and second gas diffusion layers which
are arranged on both surfaces of the electrode complex; separators
for respectively supplying reaction gas to the first and second gas
diffusion layers; and a gasket for sealing the reaction gas,
wherein the gasket is formed on a surface of the gas diffusion
layer so as to oppose to the separator, at least the gasket forming
portion of the gas diffusion layer has a lower void content than
the portion which is in contact with the catalyst layer, and the
gasket arranged in the first and second gas diffusion layers is
integrally formed so as to cover at least end portions of the first
and second gas diffusion layers.
3. A fuel cell comprising: a membrane electrode complex in which
catalyst layers are respectively arranged on both surfaces of a
electrolyte membrane; first and second gas diffusion layers which
are arranged on both surfaces of the electrode complex; separators
for respectively supplying reaction gas to the first and second gas
diffusion layers; and a gasket for sealing the reaction gas,
wherein the gasket is formed on a surface of the gas diffusion
layer so as to oppose to the separator, at least the gasket forming
portion of the gas diffusion layer has a reduced void content in
comparison with the portion which is in contact with the catalyst
layer.
4. A method of manufacturing a fuel cell gasket as claimed in claim
2, wherein an adhesive agent is applied to the gasket forming
portion having the lower void content in the gas diffusion layer,
and the gasket formed in a predetermined shape is bonded
thereon.
5. A method of manufacturing a fuel cell gasket as claimed in claim
2, wherein an adhesive agent is applied to the gasket forming
portion having the lower void content in the gas diffusion layer,
and the gasket is formed thereon in accordance with any one of an
injection molding method, a print method, a dispenser method, a
spray method and a compression molding method.
6. A method of manufacturing a fuel cell gasket as claimed in claim
2, wherein the gasket is formed in the gasket forming portion
having the lower void content in the gas diffusion layer in
accordance with any one of an injection molding method, a print
method, a dispenser method, a spray method and a compression
molding method by using an adhesive rubber as a material.
7. A method of manufacturing a fuel cell gasket as claimed in claim
2, wherein a surface roughness is secured in the gasket forming
portion having the lower void content in the gas diffusion layer,
and the gasket is formed thereon in accordance with any one of an
injection molding method, a print method, a dispenser method, a
spray method and a compression molding method.
8. A method of manufacturing a gasket of a fuel cell comprising the
steps of: arranging and bonding first and second gas diffusion
layers on both surfaces of a membrane electrode complex in which
catalyst layers are respectively arranged at least on both surfaces
of a electrolyte membrane; and thereafter forming a gasket on the
gasket diffusion layer surface facing to a separator by rubber or
resin and simultaneously carrying out an impregnation process in
the gasket forming portion of the gas diffusion layer.
Description
[0001] This is a divisional application of application Ser. No.
10/474,520, filed Oct. 23, 2003, which is an application under 35
U.S.C. 371 of PCT/JP02/04038, filed Apr. 23, 2002 and published in
Japanese.
TECHNICAL FIELD
[0002] The present invention relates to a fuel cell and a
manufacturing method of the same.
BACKGROUND ART
[0003] In conventional, as shown in FIG. 21, there has been known a
fuel cell in which an electrolyte membrane 51, catalyst electrodes
52 and 53, gas diffusion layers 54 and 55, separators 56 and 57 and
gaskets 58 and 59 are assembled in an illustrated manner. In these
constituting parts, the electrolyte membrane 51 constitutes a
membrane electrode complex (also called as a reaction electrode
portion or an MEA) together with the catalyst electrodes 52 and 53
arranged on both surfaces thereof, and the membrane electrode
complex 60 constitutes a UEA 61 together with the gas diffusion
layers 54 and 55 arranged on both surfaces thereof. Further, as
shown in FIG. 22, a gas communication groove 62 is provided in the
separators 56 and 57 in a predetermined plan layout, and a spacer
63 is arranged in this portion in place of the gasket 58 or 59.
With respect to the other portions, the gaskets 58 and 59 fixed to
the separators 56 and 57 clamp the electrolyte membrane 51 between
them so as to secure a sealing property.
[0004] However, in accordance with this prior art, since the
gaskets 58 and 59 fixed to the separators 56 and 57 clamp the
electrolyte membrane 51 between them, whereby the sealing property
is secured as mentioned above, there is a disadvantage that the
electrolyte membrane 51 tends to be broken near the gaskets 58 and
59. The electrolyte membrane 51 tends to be affected by dry and wet
due to operation and stop of the cell, and there is a risk that the
electrolyte membrane 51 is broken in a short time period due to a
great stress caused by compression and expansion of the membrane.
Further, in accordance with the prior art mentioned above, since
the spacer 63 having a high rigidity must be independently arranged
in the portion of the gas communication groove 62, an assembling
step for the cell is complex, and thus a contact state with the
electrolyte membrane 51 is different from the other portions, so
that the structure is made such that the electrolyte membrane 51
tends to be broken.
[0005] Further, in accordance with the prior art mentioned above,
since the constituting parts are sequentially assembled at a time
of assembling the cell, there is a disadvantage that the assembling
step is complex in view of this point. That is, as described above,
the fuel cell has the separator constituted by the carbon plate or
the like, the membrane electrode complex for reacting the gas, the
gas diffusion layer made of a carbon fiber or the like for
promoting a gas diffusion, and the gasket made of a rubber elastic
material or the like for sealing the gas and a refrigerant, as the
main constituting parts, however, since these constituting parts
have been conventionally assembled sequentially at a time of
assembling the fuel cell, a lot of labor and time are required for
this assembly. On the other hand, in recent years, there has been
invented an integral product of the separator and the gasket in
which the gasket is integrally formed directly on the carbon plate
(refer to Japanese Unexamined Patent Publication No. 2000-133288),
however, it is impossible to avoid the structure in which the
spacer 63 having a high rigidity is independently arranged in the
portion of the gas communication groove 62, so that the cell
assembling step becomes complex, and it is hard to carry out an
automation for the purpose of reducing the manufacturing cost, in a
stacking step of alternately stacking the separator and the
UEA.
[0006] The gas diffusion layer is made of a sintered body, a woven
fabric or a non-woven fabric of a fiber-like material such as a
carbon fiber, a metal fiber, an inorganic fiber or the like, and is
a porous body having a continuous gas permeability since a gas
permeability is required. Accordingly, a rigidity and a strength
are lower than a dense structure body, the gas diffusion layer
tends to be collapsed due to an excessive pressurization so as to
be permanently deformed, and a handling property is not good in
view of an assembling work. Accordingly, shapes of the gaskets are
not uniformed due to a breakage, a collapse or a deformation of the
gas diffusion layer caused by pressurizing for positioning or
integrating at a time of forming the gasket or assembling with the
membrane electrode complex, the separator or the like after forming
the gasket, so that there is fear that a surface pressure required
for sealing with respect to an opposing surface to the gasket is
short or excessive. Further, since the gas diffusion layer has the
porous structure, there is fear that a gas is leaked in a layer
direction of the gas diffusion layer.
[0007] The present invention is made by taking the above matter
into consideration, and an object of the present invention is to
provide a fuel cell and a manufacturing method of the same which
can effectively prevent an electrolyte membrane from being broken,
can make an assembling step for the fuel cell easy, and can achieve
material such as a carbon fiber, a metal fiber, an inorganic fiber
or the like, and is a porous body having a continuous gas
permeability since a gas permeability is required. Accordingly, a
rigidity and a strength are lower than a dense structure body, the
gas diffusion layer tends to be collapsed due to an excessive
pressurization so as to be permanently deformed, and a handling
property is not good in view of an assembling work. Accordingly,
shapes of the gaskets are not uniformed due to a breakage, a
collapse or a deformation of the gas diffusion layer caused by
pressurizing for positioning or integrating at a time of forming
the gasket or assembling with the membrane electrode complex, the
separator or the like after forming the gasket, so that there is
fear that a surface pressure required for sealing with respect to
an opposing surface to the gasket is short or excessive. Further,
since the gas diffusion layer has the porous structure, there is
fear that a gas is leaked in a layer direction of the gas diffusion
layer.
[0008] The present invention is made by taking the above matter
into consideration, and an object of the present invention is to
provide a fuel cell and a manufacturing method of the same which
can effectively prevent an electrolyte membrane from being broken,
can make an assembling step for the fuel cell easy, and can achieve
an excellent sealing property.
[0009] In this case, the present invention can be also applied to a
fuel cell which directly use a liquid fuel such as a methanol or
the like (a direct methanol fuel cell), in addition to a fuel cell
which uses a gas fuel such as a hydrogen or the like.
DISCLOSURE OF THE INVENTION
[0010] In order to achieve the object mentioned above, in
accordance with a first aspect of the present invention, there is
provided a fuel cell comprising:
[0011] a membrane electrode complex in which catalyst layers are
respectively arranged on both surfaces of a electrolyte
membrane;
[0012] first and second gas diffusion layers which are arranged on
both surfaces of the electrode complex;
[0013] separators for respectively supplying reaction gas to the
first and second gas diffusion layers; and
[0014] a gasket for sealing the reaction gas,
[0015] wherein the gasket is formed on a surface of the gas
diffusion layer so as to oppose to the separator, at least the
gasket forming portion of the gas diffusion layer has a lower void
content than the portion which is in contact with the catalyst
layer, and the gasket arranged in the first and second gas
diffusion layers is integrally formed at least via a through hole
passing through both the first and second gas diffusion layers.
[0016] Further, in accordance with a second aspect of the present
invention, there is provided a fuel cell comprising:
[0017] a membrane electrode complex in which catalyst layers are
respectively arranged on both surfaces of a electrolyte
membrane;
[0018] first and second gas diffusion layers which are arranged on
both surfaces of the electrode complex;
[0019] separators for respectively supplying reaction gas to the
first and second gas diffusion layers; and
[0020] a gasket for sealing the reaction gas,
[0021] wherein the gasket is formed on a surface of the gas
diffusion layer so as to oppose to the separator, at least the
gasket forming portion of the gas diffusion layer has a lower void
content than the portion which is in contact with the catalyst
layer, and the gasket arranged in the first and second gas
diffusion layers is connected to an insulating spacer provided on a
back surface of the gas diffusion layers via a through hole
provided in each of the gas diffusion layers.
[0022] Further, in accordance with a third aspect of the present
invention, there is provided a fuel cell comprising:
[0023] a membrane electrode complex in which catalyst layers are
respectively arranged on both surfaces of a electrolyte
membrane;
[0024] first and second gas diffusion layers which are arranged on
both surfaces of the electrode complex;
[0025] separators for respectively supplying reaction gas to the
first and second gas diffusion layers; and
[0026] a gasket for sealing the reaction gas,
[0027] wherein the gasket is formed on a surface of the gas
diffusion layer so as to oppose to the separator, at least the
gasket forming portion of the gas diffusion layer has a lower void
content than the portion which is in contact with the catalyst
layer, and the gasket arranged in the first and second gas
diffusion layers is integrally formed so as to cover at least end
portions of the first and second gas diffusion layers.
[0028] Further, in accordance with a fourth aspect of the present
invention, there is provided a fuel cell comprising:
[0029] a membrane electrode complex in which catalyst layers are
respectively arranged on both surfaces of a electrolyte
membrane;
[0030] first and second gas diffusion layers which are arranged on
both surfaces of the electrode complex;
[0031] separators for respectively supplying reaction gas to the
first and second gas diffusion layers; and
[0032] a gasket for sealing the reaction gas,
[0033] wherein the gasket is formed on a surface of the gas
diffusion layer so as to oppose to the separator, at least the
gasket forming portion of the gas diffusion layer has a reduced
void content in comparison with the portion which is in contact
with the catalyst layer.
[0034] Further, in accordance with a fifth aspect of the present
invention, there is provided a method of manufacturing a fuel cell
gasket as recited in the third aspect or the fourth aspect
mentioned above, wherein an adhesive agent is applied to the gasket
forming portion having the lower void content in the gas diffusion
layer, and the gasket formed in a predetermined shape is bonded
thereon.
[0035] Further, in accordance with a sixth aspect of the present
invention, there is provided a method of manufacturing a fuel cell
gasket as recited in the third aspect or the fourth aspect
mentioned above, wherein an adhesive agent is applied to the gasket
forming portion having the lower void content in the gas diffusion
layer, and the gasket is formed thereon in accordance with any one
of an injection molding method, a print method, a dispenser method,
a spray method and a compression molding method.
[0036] Further, in accordance with a seventh aspect of the present
invention, there is provided a method of manufacturing a fuel cell
gasket as recited in the third aspect or the fourth aspect
mentioned above, wherein the gasket is formed in the gasket forming
portion having the lower void content in the gas diffusion layer in
accordance with anyone of an injection molding method, a print
method, a dispenser method, a spray method and a compression
molding method by using an adhesive rubber as a material.
[0037] Further, in accordance with an eighth aspect of the present
invention, there is provided a method of manufacturing a fuel cell
gasket as recited in the third aspect or the fourth aspect
mentioned above, wherein a surface roughness is secured in the
gasket forming portion having the lower void content in the gas
diffusion layer, and the gasket is formed thereon in accordance
with any one of an injection molding method, a print method, a
dispenser method, a spray method and a compression molding
method.
[0038] Further, in accordance with a ninth aspect of the present
invention, there is provided a fuel cell as recited in any one of
the first aspect to the fourth aspect mentioned above, wherein the
void content of the gasket forming portion is reduced by
impregnating any one of rubber, resin, carbon and an inorganic
material in the gasket forming portion of the gas diffusion
layer.
[0039] Further, in accordance with a tenth aspect of the present
invention, there is provided a fuel cell as recited in any one of
the first aspect to the fourth aspect mentioned above, wherein a
bulk density is made high in the gasket forming portion of the gas
diffusion layer, and the void content is reduced in the gasket
forming portion of the gas diffusion layer.
[0040] Further, in accordance with an eleventh aspect of the
present invention, there is provided a fuel cell as recited in any
one of the first aspect to the fourth aspect mentioned above,
wherein a gasket made of a rubber-like elastic material is formed
after previously impregnating any one of rubber, resin, carbon and
an inorganic material in the gasket forming portion of the gas
diffusion layer, and bonding a membrane electrode complex to the
first and second gas diffusion layers.
[0041] Further, in accordance with a twelfth aspect of the present
invention, there is provided a gas diffusion layer for a fuel cell,
the gas diffusion layer being used in the fuel cell as recited in
any one of the first aspect to the fourth aspect mentioned above,
wherein rubber or resin is impregnated in the gasket forming
portion of the gas diffusion layer, and an insulating spacer made
of rubber or resin is formed on one surface of the impregnation
portion.
[0042] Further, in accordance with a thirteenth aspect of the
present invention, there is provided a gas diffusion layer for a
fuel cell, the gas diffusion layer being used in the fuel cell as
recited in any one of the first aspect to the fourth aspect
mentioned above, wherein rubber or resin is impregnated in the
gasket forming portion of the gas diffusion layer, and a gasket
made of a rubber-like elastic material is formed at least in the
gasket forming portion of the gas diffusion layer.
[0043] Further, in accordance with a fourteenth aspect of the
present invention, there is provided a method of manufacturing a
gasket of a fuel cell recited in any one of the first aspect to the
fourth aspect mentioned above, comprising the steps of:
[0044] arranging and bonding first and second gas diffusion layers
on both surfaces of a membrane electrode complex in which catalyst
layers are respectively arranged at least on both surfaces of a
electrolyte membrane; and
[0045] thereafter forming a gasket on the gasket diffusion layer
surface facing to a separator by rubber or resin and simultaneously
carrying out an impregnation process in the gasket forming portion
of the gas diffusion layer.
[0046] Further, in accordance with a fifteenth aspect of the
present invention, there is provided a fuel cell as recited in any
one of the first aspect to the fourth aspect mentioned above,
wherein the gaskets are provided at corresponding positions with
respect to the membrane electrode complex, in portions in which the
gaskets are formed on the surfaces of the first and second gas
diffusion layers so as to face to the separator.
[0047] Further, in accordance with a sixteenth aspect of the
present invention, there is provided a fuel cell as recited in any
one of the first aspect to the fourth aspect mentioned above,
wherein a groove which receives at least the gasket is formed in
the separator, the groove is shallower than the height of the
gasket, and a cross sectional area thereof is larger than a cross
sectional area of the gasket.
[0048] Further, in accordance with a seventeenth aspect of the
present invention, there is provided a fuel cell as recited in any
one of the first aspect to the fourth aspect mentioned above,
wherein an outer size of the electrolyte membrane is smaller than
an outer size of the gas diffusion layer, and electrolyte membrane
is arranged in an inner portion of a surfaces of the gas diffusion
layers.
[0049] In accordance with the fuel cell on the basis of the first
aspect of the present invention provided with the structure
mentioned above, it becomes possible to easily form the gaskets
respectively formed on the surfaces of the first and second gas
diffusion layers so as to face to the separator, at the
corresponding positions with respect to the membrane electrode
complex. Further, since it is possible to integrally form the
gasket via the through hole commonly passing through the first and
second gas diffusion layers, it is possible to form the gaskets on
both surfaces by one step. Further, since the gasket is integrally
formed via the through hole commonly passing through the first and
second gas diffusion layers, whereby it is possible to securely fix
the gasket to the gas diffusion layer, it is possible to prevent
the gasket from coming off from the gas diffusion layer and from
being displaced. Further, it is possible to optionally set the
height of the gasket without relation to the thickness of the UEA
in the gasket forming portion.
[0050] Further, in accordance with the fuel cell on the basis of
the second aspect of the present invention provided with the
structure mentioned above, it is possible to integrally form the
gasket material impregnated portion as well as the gasket and the
insulating spacer are integrally formed. Further, since the gasket
and the insulating spacer are connected via the through hole
provided in the first or second gas diffusion layer, whereby it is
possible to securely fix the gasket and the insulating spacer to
the gas diffusion layer, it is possible to prevent the gasket from
coming off from the gas diffusion layer and from being
displaced.
[0051] Further, in accordance with the fuel cell on the basis of
the third aspect of the present invention provided with the
structure mentioned above, it is possible to easily form the
gaskets respectively formed on the surfaces of the first and second
gas diffusion layers so as to face to the separator, at the
corresponding positions with respect to the membrane electrode
complex. Further, since the gasket is integrally formed so as to
cover the end portions of the first and second gas diffusion
layers, it is possible to form the gaskets on both surfaces by one
step, and it is possible to form the gasket in a C shape at an end
portion of the UEA, whereby it is possible to securely prevent the
reaction gas from leaking from the end portion of the gas diffusion
layer, an interface of the gas diffusion layer and the insulating
spacer, or the interface of the insulating spacers as well as it is
possible to secure the insulation in the end portion of the
UEA.
[0052] Further, in accordance with the fuel cell on the basis of
the fourth aspect of the present invention provided with the
structure mentioned above, it becomes possible to easily form the
gaskets respectively formed on the surfaces of the first and second
gas diffusion layers so as to face to the separator, at the
corresponding positions with respect to the membrane electrode
complex, by forming the gasket after previously integrating the
UEA. Further, since the gasket is formed after integrating the UEA,
it is possible to form the gaskets on both surfaces by one step.
Further, it is possible to fix the gasket to the gasket diffusion
layer by simultaneously carrying out the previous impregnation of
the gasket material in the gasket forming portion and the forming
of the gasket, before integrating the UEA.
[0053] Further, in addition to the operation in the third aspect or
the fourth aspect of the present invention mentioned above, in
accordance with the manufacturing method on the basis of the fifth
aspect of the present invention provided with the structure
mentioned above, it becomes possible to fix the gasket to the gas
diffusion layer by applying the adhesive agent to the gasket
forming portion.
[0054] Further, in accordance with the manufacturing method on the
basis of the sixth aspect of the present invention provided with
the structure mentioned above, in addition to the same operation as
that of the fifth aspect of the present invention mentioned above,
it becomes possible to fix the gasket to the gas diffusion layer by
applying the adhesive agent to the gasket forming portion. Further,
in accordance with the present forming method, it is possible to
carry out a lot of processes in a short time.
[0055] Further, in accordance with the manufacturing method on the
basis of the seventh aspect of the present invention provided with
the structure mentioned above, the same operation as that of the
sixth aspect mentioned above can be achieved by using the adhesive
rubber material.
[0056] Further, in accordance with the manufacturing method on the
basis of the eighth aspect of the present invention provided with
the structure mentioned above, the same operation as that of the
sixth aspect mentioned above can be achieved by securing the
surface roughness of the gas diffusion layer and forming the gasket
thereon.
[0057] Further, in addition to the operation in any one of the
first aspect to the fourth aspect of the present invention
mentioned above, in accordance with the fuel cell on the basis of
the ninth aspect of the present invention provided with the
structure mentioned above, in addition to the same operation as
that of the first aspect to the fourth aspect mentioned above, it
becomes possible to easily reduce a void content by impregnating
the material described as a filler in the void of the gas diffusion
layer. The filler may be the same kind as the material forming the
gas diffusion layer or different therefrom.
[0058] Further, in accordance with the fuel cell on the basis of
the tenth aspect of the present invention provided with the
structure mentioned above, in addition to the same operation as
that of the first aspect to the fourth aspect mentioned above, it
becomes possible to reduce the void content by making a bulk
density high. In this case, in the tenth aspect, the void content
is reduced by increasing a provision amount of the gasket forming
portion at a time of manufacturing the gas diffusion layer, or
compressing the gasket forming portion. In the latter case of
reducing the void content by compressing the gasket forming
portion, since only the gasket forming portion is excessively
compressed even when the provision amount is fixed, the void space
in this portion is a little, and only this portion is formed
thinner than the other portions.
[0059] Further, in accordance with the fuel cell on the basis of
the eleventh aspect of the present invention provided with the
structure mentioned above, in addition to the same operation as
that of the first aspect to the fourth aspect mentioned above, it
becomes possible to select a material which is most suitable for
the respective processes in the case of setting the material
impregnated in the gas diffusion layer different from the gasket
material. Further, it is possible to make a rigidity or a strength
of the impregnation portion high by impregnating the filler
described in the present aspect in the gas diffusion layer, and it
is possible to make it easy to fix a carbon fiber of the gas
diffusion layer.
[0060] Further, in accordance with the gas diffusion layer on the
basis of the twelfth aspect of the present invention provided with
the structure mentioned above, in addition to the same operation as
that of the first aspect to the fourth aspect mentioned above, it
is possible to make the rigidity or the strength of the
impregnation portion high by impregnating the filler described in
the present aspect in the gas diffusion layer, and it is possible
to entrench the carbon fiber of the gas diffusion layer. Further,
since the insulating spacer is fixed to the gas diffusion layer, it
becomes possible to make it easy to integrally bond the UEA.
[0061] Further, in accordance with the gas diffusion layer on the
basis of the thirteenth aspect of the present invention provided
with the structure mentioned above, it is possible to achieve the
same operation as that of the first aspect to the fourth aspect
mentioned above.
[0062] Further, in accordance with the manufacturing method on the
basis of the fourteenth aspect of the present invention provided
with the structure mentioned above, in addition to the same
operation as that of the first aspect to the fourth aspect
mentioned above, since the gasket forming and the impregnating
process can be carried out at the same time, it becomes possible to
shorten the process.
[0063] Further, in accordance with the fuel cell on the basis of
the fifteenth aspect of the present invention provided with the
structure mentioned above, it is possible to achieve the same
operation as that of the first aspect to the fourth aspect
mentioned above.
[0064] Further, in accordance with the fuel cell on the basis of
the sixteenth aspect of the present invention provided with the
structure mentioned above, in addition to the same operation as
that of the first aspect to the fourth aspect mentioned above, the
gasket is received in the groove formed in the separator, and the
gasket is completely received within the groove at a time of
fastening the stack. Further, the UEA and the separator are in
contact with each other in the end portion in the same manner as
the center portion.
[0065] Further, in accordance with the fuel cell on the basis of
the seventeenth aspect of the present invention provided with the
structure mentioned above, in addition to the same operation as
that of the first aspect to the fourth aspect mentioned above, it
becomes possible to reduce a used amount of the electrolyte
membrane which is comparatively expensive.
[0066] The expression "the void content is low" or "make the void
content low" in each of the aspects mentioned above means making
the rigidity or the strength of this portion high by making the
void content of the gasket forming portion lower than the other
portions, and means making it easy to form the gasket by forming
the gasket on the portion having the low void content and having
the structure mentioned above. Further, since the size, the shape
and the like of the gasket to be formed are standardized (it is
easy to form in a planned shape) it is possible to secure an
excellent sealing property, and this means that it becomes possible
to make an assembling work easy. Further, since the gas diffusion
layer has a porous structure, it also means that it is possible to
achieve an effect of preventing the gas from leaking in the layer
direction of the gas diffusion layer. The impregnation material is
impregnated appropriately at a required amount in correspondence to
the hardness or the like, and the rate of impregnation is different
in correspondence to the rigidity and the shape of the material to
be impregnated, the impregnating method or the like.
[0067] The void content of the gas diffusion layer is generally
between 60 and 90%, and when the void content of the gasket forming
portion is low in comparison with the portion being in contact with
the catalyst layer, it approximately corresponds to 2% to 100% of
the void, depending upon the hardness and the shape of the filler
and the impregnating method, and it is generally about 50% or
more.
[0068] As the adhesive agent applied to the gasket forming portion
in the gas diffusion layer, in correspondence to the kind of the
rubber used as the gasket, there is suitably used a silicone
adhesive agent, a phenol adhesive agent, an epoxy adhesive agent,
an acrylic adhesive agent, an adhesive agent based on a
thermoplastic resin, a thermosetting resin or a rubber such as a
chroman indene adhesive agent or the like, an adhesive primer such
as a silane coupling agent, a titanium coupling agent or the like
containing a functional group such as an epoxy group, an amino
group, a vinyl group or the like, and an adhesive agent obtained by
blending the adhesive primer in the thermoplastic resin adhesive
agent, the thermosetting adhesive agent or the rubber adhesive
agent.
[0069] With respect to the surface roughness of the gasket forming
portion in the gas diffusion layer, if it is 0.1 .mu.m or more,
preferably, 1 .mu.m or more, it is convenient for the surface
roughness by which the adhesion with the rubber forming the gasket
can be sufficiently secured. Since the gas diffusion layer itself
generally has a porous structure, there is a structure which is
within the surface roughness range, however, it is necessary to
appropriately secure the surface roughness which is sufficient for
the adhesion, in accordance with the filler, the amount thereof,
the impregnating method and the like.
[0070] As described above, as the material to be impregnated (the
impregnation material), rubber, resin, carbon, an inorganic
material or the like is proper.
[0071] Among them, first, as the rubber to be impregnated, there is
used a saturation type rubber such as an ethylene propylene rubber,
a fluorine-contained rubber, a silicon rubber, a fluorosilicon
rubber, a butyl rubber, a hydrogenated styrene butadiene rubber, a
hydrogenated styrene isoprene rubber, an acrylic rubber, a
fluoroacrylic rubber, and the like, or a saturation type elastomer
such as a polyester elastomer, a polyolefine elastomer, a polyamide
elastomer and the like. They are impregnated by heating and
pressurizing, or a solution thereof or a latex thereof is
impregnated. Further, there is used a saturation type liquid rubber
such as a liquid silicon rubber, a liquid fluorosilicon rubber, a
liquid fluorine-contained rubber, a liquid butyl rubber, a liquid
ethylene propylene rubber and the like, and they are impregnated by
heating or pressuring, or heating and pressurizing, or forming the
solution thereof.
[0072] As the resin to be impregnated, there is used a
thermosetting resin, a thermoplastic resin or the like. Since the
thermosetting resin is in a liquid state at a room temperature or
is liquefied by being heated, it is used as it is or being diluted
by a solvent or the like. In the case of the thermoplastic resin,
it is used by being heated and pressurized, being diluted by the
solvent or the like or as an emulsion. The impregnating method is
appropriately selected from the methods mentioned above in
correspondence to a nature (mainly a viscosity) thereof. As the
thermosetting resin, there is used a silicon resin, an epoxy resin,
a phenol resin, a thermosetting polyimide resin, a diallyl
phthalate resin or the like, and a prepolymer of the thermosetting
resin is impregnated in the gas diffusion layer. As the
thermoplastic resin, a polyolefine resin, a polysulfone resin, a
polyester resin, a polyamide resin, a polyimide resin, a polyamide
imide resin, a polycarbonate resin, a fluorine-contained resin,
polyether imide, a polyether ether ketone, a polystyrene, a
polyphenylene sulfide, a polyphenylene ether, or the like, and the
resin is made in a heated and molten state, in a solution state by
being dissolved in a good solvent, or in a dispersion state in
which the resin is dispersed into the liquid such as the water or
the like in a fine particle state, thereby being impregnated in the
gas diffusion layer. The viscosity of the prepolymer or the
dispersion liquid may be set within a range capable of being
impregnated in the gas diffusion layer, and the viscosity is
different in correspondence to the impregnating method and the
impregnating condition, however, is about 10.sup.0 to 10.sup.4
Pas.
[0073] As the carbon to be impregnated, there is used a carbon
powder, a carbon black, a graphite powder, a carbon fiber, a
graphite fiber or the like, and, for example, a fine particle is
dispersed into a liquid so as to be impregnated in accordance with
a pressurizing spray, a pressurizing injection or the like.
Further, the fine particle may be added to the resin solution or
the resin dispersion liquid so as to be impregnated in accordance
with the method as described in the seventh aspect of the present
invention or the like in correspondence to the nature (mainly the
viscosity) thereof.
[0074] As the inorganic material to be impregnated, there is used a
glass powder, a glass fiber, a material which is changed from a sol
to a gel so as to become an inorganic material, or the like.
Further, the fine particle may be added to the rubber, the resin
solution or the resin dispersion liquid so as to be impregnated in
accordance with the method as described in the seventh aspect of
the present invention or the like in correspondence to the nature
(mainly the viscosity) thereof.
[0075] The rubber used as the gasket is obtained by forming the
same group of rubber or the different rubbers in accordance with
the method as described in the seventh aspect of the present
invention or the like in correspondence to the nature (mainly the
viscosity) thereof, in the same manner as the rubber impregnated in
the gasket portion of the gas diffusion layer. For example, in the
case of the liquid rubber, it is possible to use any methods
described in the seventh aspect of the present invention. In the
case of the rubber having a high viscosity, a normal injection
molding method or compression molding method is used. As the
adhesive rubber, it is possible to use a rubber in which the rubber
itself has an adhesive property, a rubber in which an adhesion
improving agent applying an adhesion to the rubber is added, and
the like, and as an example thereof, it is possible to list up a
self-adhesion liquid silicon rubber, a self-adhesion liquid
fluorine-contained rubber, a rubber in which an epoxy adhesive
agent or a phenol adhesive agent is blended in the
fluorine-contained rubber.
[0076] The insulating spacer can be formed by a liquid rubber, a
thermosetting resin or a thermoplastic resin. In the case of using
the liquid rubber, it is possible to use the same material as the
liquid rubber impregnated in the gas diffusion layer or the liquid
rubber forming the gasket, and it is possible to simultaneously
form. Further, in the case of using the thermosetting resin or the
thermoplastic resin, it is possible to use the same kind as the
resin impregnated in the gas diffusion layer, and it is possible to
simultaneously form. Of course, it is possible to independently
form on the basis of the different kind of material from the
material mentioned above. As the thermoplastic resin,
fluorine-contained resin such as polytetrafluoroethylene (PTFE) or
the like, polyolefine or the like is suitable.
BRIEF DESCRIPTION OF THE DRAWINGS
[0077] FIG. 1 is a cross sectional view of a main portion of a fuel
cell in accordance with a first embodiment of the present
invention;
[0078] FIG. 2 is a cross sectional view of a main portion of a fuel
cell in accordance with a second embodiment of the present
invention;
[0079] FIG. 3 is a cross sectional view of a main portion of a fuel
cell in accordance with a third embodiment of the present
invention;
[0080] FIG. 4 is a cross sectional view of a main portion of a fuel
cell in accordance with a fourth embodiment of the present
invention;
[0081] FIG. 5 is a cross sectional view of a main portion of a fuel
cell in accordance with a fifth embodiment of the present
invention;
[0082] FIG. 6 is a cross sectional view of a main portion of a fuel
cell in accordance with a sixth embodiment of the present
invention;
[0083] FIG. 7 is a cross sectional view of a main portion of a fuel
cell in accordance with a seventh embodiment of the present
invention;
[0084] FIG. 8 is a cross sectional view of a main portion of a fuel
cell in accordance with an eighth embodiment of the present
invention;
[0085] FIG. 9 is a cross sectional view of a main portion of a fuel
cell in accordance with a ninth embodiment of the present
invention;
[0086] FIG. 10 is a cross sectional view of a main portion of a
fuel cell in accordance with a tenth embodiment of the present
invention;
[0087] FIG. 11 is a cross sectional view of a main portion of a gas
diffusion layer in accordance with an eleventh embodiment of the
present invention;
[0088] FIG. 12 is a cross sectional view of a main portion of a gas
diffusion layer in accordance with a twelfth embodiment of the
present invention;
[0089] FIG. 13 is a cross sectional view of a main portion of a gas
diffusion layer in accordance with a thirteenth embodiment of the
present invention;
[0090] FIGS. 14A and 14B are cross sectional views of a main
portion of a gas diffusion layer in accordance with a fourteenth
embodiment of the present invention;
[0091] FIG. 15 is a schematic view describing a step in a method of
manufacturing a fuel cell in accordance with a fifteenth embodiment
of the present invention;
[0092] FIG. 16 is a schematic view describing the step in the
method of manufacturing the fuel cell in accordance with the
fifteenth embodiment of the present invention;
[0093] FIG. 17 is a schematic view describing the step in the
method of manufacturing the fuel cell in accordance with the
fifteenth embodiment of the present invention;
[0094] FIG. 18 is a schematic view describing the step in the
method of manufacturing the fuel cell in accordance with the
fifteenth embodiment of the present invention;
[0095] FIG. 19 is a schematic view describing the step in the
method of manufacturing the fuel cell in accordance with the
fifteenth embodiment of the present invention;
[0096] FIG. 20 is a schematic view describing the step in the
method of manufacturing the fuel cell in accordance with the
fifteenth embodiment of the present invention;
[0097] FIG. 21 is a cross-sectional view of a main portion of a
fuel cell in accordance with a conventional art; and
[0098] FIG. 22 is a cross sectional view of a main portion of a
fuel cell in accordance with a conventional art.
BEST MODE FOR CARRYING OUT THE INVENTION
[0099] Next, a description will be given of embodiments in
accordance with the present invention with reference to the
accompanying drawings.
First Embodiment
[0100] FIG. 1 shows a first embodiment in which a gasket is formed
after previously inserting a sheet made of a different material
from a gasket as an insulating spacer so as to form an UEA.
[0101] That is, catalyst layers 3 and 4 are arranged on both
surfaces of an electrolyte membrane 2 so as to form a membrane
electrode complex 1, gas diffusion layers 5 and 6 are arranged on
both surfaces of the membrane electrode complex 1 so as to form an
UEA 7, and separators 8 and 9 are arranged on both surfaces of the
UEA 7. The gas diffusion layers 5 and 6 constituted by a porous
body such as a carbon fiber or the like are structured such that a
size thereof is set to be larger than a size of the catalyst layers
3 and 4, a gasket forming material is previously impregnated in a
protruding portion in a plan direction, whereby impregnation
portions 10 and 11 having a comparatively low void content are
formed, and insulating spacers 12 and 13 constituted by a sheet
made of a different material from that of the gaskets 15 and 16 are
interposed between the impregnation portions 10 and 11. A desired
number of through holes 14 are formed in the impregnation portions
10 and 11 and the insulating spacers 12 and 13 in such a manner as
to extend therethrough in a thickness direction. The gaskets 15 and
16 made of a rubber-like elastic material are arranged on surfaces
of the impregnation portions 10 and 11 corresponding to the gasket
forming portions in the gas diffusion layers 5 and 6 so as to face
to the separators 8 and 9, and the gaskets 15 and 16 are integrally
formed with each other via the thorough holes 14. Groove-like
gasket receiving portions 17 and 18 are formed in the separators 8
and 9 so as to correspond to the gaskets 15 and 16. The electrolyte
membrane 2 is set smaller in a size than a size of the gas
diffusion layers 5 and 6. Accordingly, the electrolyte membrane 2
does not reach the through hole 14. It is sufficient that the
electrolyte membrane 2 protrudes at least more than the end
portions of the catalyst layers 3 and 4.
Second Embodiment
[0102] FIG. 2 shows a second embodiment in which a gasket is formed
after previously inserting a sheet made of a different material
from the gasket as an insulating spacer so as to form the UEA.
[0103] That is, the catalyst layers 3 and 4 are arranged on both
surfaces of the electrolyte membrane 2 so as to form the membrane
electrode complex 1, the gas diffusion layers 5 and 6 are arranged
on both surfaces of the membrane electrode complex 1 so as to form
the UEA 7, and the separators 8 and 9 are arranged on both surfaces
of the UEA 7. The gas diffusion layers 5 and 6 constituted by a
porous body such as a carbon fiber or the like are structured such
that the size thereof is set to be larger than the size of the
catalyst layers 3 and 4, the gasket forming material is previously
impregnated in a protruding portion in a plan direction, whereby
the impregnation portions 10 and 11 having a comparatively low void
content are formed, and the insulating spacers 12 and 13
constituted by a sheet made of a different material from that of
the gaskets 15 and 16 are interposed between the impregnation
portions 10 and 11. A desired number of through holes 14 are formed
in the impregnation portions 10 and 11 and the insulating spacers
12 and 13 in such a manner as to extend therethrough in a thickness
direction. The gaskets 15 and 16 made of a rubber-like elastic
material are arranged on surfaces of the impregnation portions 10
and 11 corresponding to the gasket forming portions in the gas
diffusion layers 5 and 6 so as to face to the separators 8 and 9,
and the gaskets 15 and 16 are integrally formed with each other via
the thorough holes 14. The groove-like gasket receiving portions 17
and 18 are formed in the separators 8 and 9 so as to correspond to
the gaskets 15 and 16. The electrolyte membrane 2 is set equal in a
size to the size of the gas diffusion layers 5 and 6. Accordingly,
the electrolyte membrane 2 reaches the through hole 14, whereby the
through hole 14 is also formed in the electrolyte membrane 2. The
impregnating process of the impregnation portions 10 and 11 may be
previously carried out prior to the integrating process, or may be
carried out at the same time of forming the gaskets 15 and 16 after
integrating the UEA 7.
Third Embodiment
[0104] FIG. 3 shows an embodiment in which a gasket is formed after
previously forming an insulating spacer by the same material as the
gasket material of the impregnation portion so as to form the
UEA.
[0105] That is, the catalyst layers 3 and 4 are arranged on both
surfaces of the electrolyte membrane 2 so as to form the membrane
electrode complex 1, the gas diffusion layers 5 and 6 are arranged
on both surfaces of the membrane electrode complex 1 so as to form
the UEA 7, and the separators 8 and 9 are arranged on both surfaces
of the UEA 7. The gas diffusion layers 5 and 6 constituted by a
porous body such as a carbon fiber or the like are structured such
that the size thereof is set to be larger than the size of the
catalyst layers 3 and 4, the gasket forming material is previously
impregnated in a protruding portion in a plan direction, whereby
the impregnation portions 10 and 11 having a comparatively low void
content are formed, and the insulating spacers 12 and 13 made of
the same kind of material as that of the gasket material
impregnation portions 10 and 11 are arranged between the
impregnation portions 10 and 11 in accordance with an integral
molding. A desired number of through holes 14 are formed in the
impregnation portions 10 and 11 and the insulating spacers 12- and
13 in such a manner as to extend therethrough in a thickness
direction. The gaskets 15 and 16 made of a rubber-like elastic
material are arranged on surfaces of the impregnation portions 10
and 11 corresponding to the gasket forming portions in the gas
diffusion layers 5 and 6 so as to face to the separators 8 and 9,
and the gaskets 15 and 16 are integrally formed with each other via
the thorough holes 14. The groove-like gasket receiving portions 17
and 18 are formed in the separators 8 and 9 so as to correspond to
the gaskets 15 and 16. The electrolyte membrane 2 is set smaller in
size than the size of the gas diffusion layers 5 and 6. However,
this size may be equal to the size of the gas diffusion layers 5
and 6, and in this case, the through hole 14 is formed in the
electrolyte membrane 2.
Fourth Embodiment
[0106] FIG. 4 shows an embodiment in which a gasket is formed after
forming the UEA by setting the electrolyte membrane to the
insulating spacer. In accordance with this embodiment, even when
the thickness of the UEA portion of the gasket forming portion is
thinner than a reaction portion, it is possible to form a suitable
gasket.
[0107] That is, the catalyst layers 3 and 4 are arranged on both
surfaces of the electrolyte membrane 2 so as to form the membrane
electrode complex 1, the gas diffusion layers 5 and 6 are arranged
on both surfaces of the membrane electrode complex 1 so as to form
the UEA 7, and the separators 8 and 9 are arranged on both surfaces
of the UEA 7. The gas diffusion layers 5 and 6 constituted by a
porous body such as a carbon fiber or the like are structured such
that the size thereof is set to be larger than the size of the
catalyst layers 3 and 4, the gasket forming material is previously
impregnated in a protruding portion in a plan direction, whereby
the impregnation portions 10 and 11 having a comparatively low void
content are formed. As is different from the first to third
embodiments mentioned above, the specific insulating spacer is not
arranged between the impregnation portions 10 and 11, and the
electrolyte membrane 2 doubles as a function of the insulating
spacer so as to be directly in contact with the impregnation
portions 10 and 11 of the gas diffusion layers 5 and 6. The
impregnation portions 10 and 11 are deformed in a focusing
direction by a rubber forming the gaskets 15 and 16, for the
purpose of bringing the electrolyte membrane 2 into contact
therewith. A desired number of through holes 14 are formed in the
impregnation portions 10 and 11 and the electrolyte membrane 2 in
such a manner as to extend therethrough in a thickness direction.
The gaskets 15 and 16 made of a rubber-like elastic material are
arranged on surfaces of the impregnation portions 10 and 11
corresponding to the gasket forming portions in the gas diffusion
layers 5 and 6 so as to face to the separators 8 and 9, and the
gaskets 15 and 16 are integrally formed with each other via the
thorough holes 14. The groove-like gasket receiving portions 17 and
18 are formed in the separators 8 and 9 so as to correspond to the
gaskets 15 and 16. The size of the electrolyte membrane 2 is set
equal to the size of the gas diffusion layers 5 and 6.
Fifth Embodiment
[0108] FIG. 5 shows an embodiment in which the UEA is formed after
the insulating spacer and the gasket are previously formed
integrally.
[0109] That is, the catalyst layers 3 and 4 are arranged on both
surfaces of the electrolyte membrane 2 so as to form the membrane
electrode complex 1, the gas diffusion layers 5 and 6 are arranged
on both surfaces of the membrane electrode complex 1 so as to form
the UEA 7, and the separators 8 and 9 are arranged on both surfaces
of the UEA 7. The gas diffusion layers 5 and 6 constituted by a
porous body such as a carbon fiber or the like are structured such
that the size thereof is set to be larger than the size of the
catalyst layers 3 and 4, the gasket forming material is previously
impregnated in a protruding portion in a plan direction, whereby
the impregnation portions 10 and 11 having a comparatively low void
content are formed, and the insulating spacers 12 and 13 made of
the same material as that of the gaskets 15 and 16 are respectively
interposed between the impregnation portions 10 and 11. The through
holes 14 are formed in the impregnation portions 10 and 11 in such
a manner as to extend therethrough in a thickness direction. The
gaskets 15 and 16 made of a rubber-like elastic material are
arranged on surfaces of the impregnation portions 10 and 11
corresponding to the gasket forming portions in the gas diffusion
layers 5 and 6 so as to face to the separators 8 and 9, and the
gaskets 15 and 16 are integrally formed with the insulating spacers
12 and 13 via the thorough holes 14, respectively. The groove-like
gasket receiving portions 17 and 18 are formed in the separators 8
and 9 so as to correspond to the gaskets 15 and 16. The electrolyte
membrane 2 is set smaller in size than the size of the gas
diffusion layers 5 and 6, however, may have the size equal to the
size of the gas diffusion layers 5 and 6.
[0110] In this case, in the present embodiment, there is shown the
embodiment in which the insulating spacers 12 and 13 are separated,
however, the insulating spacers 12 and 13 may be formed as an
integrated insulating spacer.
Sixth Embodiment
[0111] FIG. 6 shows another embodiment in which the UEA is formed
after the insulating spacer and the gasket are previously formed
integrally. The gaskets 15 and formed in the impregnation portions
10 and 11 of the gas diffusion layers 5 and 6 and the insulating
spacers 12 and 13 are integrally formed respectively. The gaskets
15 and 16 and the insulating spacers 12 and 13 are integrally
formed respectively by impregnating the impregnation portions 10
and 11 with a phenol resin, thereafter opening the through holes
14, arranging the insulating spacers 12 and 13 constituted by a
thermoplastic resin sheet, and forming the gaskets 15 and 16 by a
liquid silicon rubber.
Seventh Embodiment
[0112] FIG. 7 shows another embodiment in which the UEA is formed
after the insulating spacer and the gasket are previously formed
integrally. The gaskets 15 and 16 formed in the impregnation
portions 10 and 11 of the gas diffusion layers 5 and 6 and the
insulating spacers 12 and 13 are integrally formed respectively.
The through holes 14 are opened in the gas diffusion layers 5 and
6, the insulating spacers 12 and 13 constituted bya thermoplastic
resin sheet are arranged, the impregnation of the silicon rubber in
the impregnation portions 10 and 11 and the forming of the gaskets
15 and 16 by the liquid silicon rubber are simultaneously carried
out, and the gaskets 15 and 16 and the insulating spacers 12 and 13
are integrally formed respectively.
Eighth Embodiment
[0113] FIG. 8 shows a third embodiment in which the gasket is
formed after the UEA is formed by previously inserting the sheet
made of the different material from that of the gasket as the
insulating spacer.
[0114] That is, the catalyst layers 3 and 4 are arranged on both
surfaces of the electrolyte membrane 2 so as to form the membrane
electrode complex 1, the gas diffusion layers 5 and 6 are arranged
on both surfaces of the membrane electrode complex 1 so as to form
the UEA 7, and the separators 8 and 9 are arranged on both surfaces
of the UEA 7. The gas diffusion layers 5 and 6 constituted by a
porous body such as a carbon fiber or the like are structured such
that the size thereof is set to be larger than the size of the
catalyst layers 3 and 4, the gasket forming material is previously
impregnated in a protruding portion in a plan direction, whereby
the impregnation portions 10 and 11 having a comparatively low void
content are formed, and the insulating spacers 12 and 13
constituted by the sheet made of the different material from that
of the gaskets 15 and 16 are interposed between the impregnation
portions 10 and 11. The gaskets 15 and 16 made of a rubber-like
elastic material are arranged on surfaces of the impregnation
portions 10 and 11 corresponding to the gasket forming portions in
the gas diffusion layers 5 and 6 so as to face to the separators 8
and 9, and the gaskets 15 and 16 are integrally formed with each
other via a connection portion 19 formed in an approximately C
cross sectional shape. The connection portion 19 covers the end
portions of the gas diffusion layers 5 and 6, and simultaneously
covers the end portions of the insulating spacers 12 and 13. The
stepped gasket receiving portions 17 and 18 are formed in the
separator so as to correspond to the gaskets 15 and 16. The
electrolyte membrane 2 is set smaller in size than the size of the
gas diffusion layers 5 and 6, however, may have the size equal to
the size of the gas diffusers 5 and 6.
Ninth Embodiment
[0115] FIG. 9 shows a fourth embodiment in which the gasket is
formed after the UEA is formed by previously inserting the sheet
made of the different material from that of the gasket as the
insulating spacer.
[0116] That is, the catalyst layers 3 and 4 are arranged on both
surfaces of the electrolyte membrane 2 so as to form the membrane
electrode complex 1, the gas diffusion layers 5 and 6 are arranged
on both surfaces of the membrane electrode complex 1 so as to form
the UEA 7, and the separators 8 and 9 are arranged on both surfaces
of the UEA 7. The gas diffusion layers 5 and 6 constituted by a
porous body such as a carbon fiber or the like are structured such
that the size thereof is set to be larger than the size of the
catalyst layers 3 and 4, the gasket forming material is previously
impregnated in a protruding portion in a plan direction, whereby
the impregnation portions 10 and 11 having a comparatively low void
content are formed, and the insulating spacers 12 and 13
constituted by the sheet made of the different material from that
of the gaskets 15 and 16 are interposed between the impregnation
portions 10 and 11. The gaskets 15 and 16 made of a rubber-like
elastic material are arranged on surfaces of the impregnation
portions 10 and 11 corresponding to the gasket forming portions in
the gas diffusion layers 5 and 6 so as to face to the separators 8
and 9, and the gaskets 15 and 16 are respectively bonded to the
impregnation portions 10 and 11 by an adhesive agent or the like.
The groove-like gasket receiving portions 17 and 18 are formed in
the separators 8 and 9 so as to correspond to the gaskets 15 and
16. The electrolyte membrane 2 is set smaller in size than the size
of the gas diffusion layers 5 and 6, however, may have the size
equal to the size of the gas diffusers 5 and 6.
Tenth Embodiment
[0117] FIG. 10 shows an embodiment in which the impregnation of the
gasket material, the forming of the gasket and the forming of the
insulating spacer are previously carried out with respect to the
gasket material impregnation portion before the UEA is integrally
formed.
[0118] That is, the catalyst layers 3 and 4 are arranged on both
surfaces of the electrolyte membrane 2 so as to form the membrane
electrode complex 1, the gas diffusion layers 5 and 6 are arranged
on both surfaces of the membrane electrode complex 1 so as to form
the UEA 7, and the separators 8 and 9 are arranged on both surfaces
of the UEA 7. The gas diffusion layers 5 and 6 constituted by a
porous body such as a carbon fiber or the like are structured such
that the size thereof is set to be larger than the size of the
catalyst layers 3 and 4, the gasket forming material is previously
impregnated in a protruding portion in a plan direction, whereby
the impregnation portions 10 and 11 having a comparatively low void
content are formed, and the insulating spacers 12 and 13 made of
the same kind of material as that of the gaskets 15 and 16 are
interposed between the impregnation portions 10 and 11. The gaskets
15 and 16 made of a rubber-like elastic material are arranged on
surfaces of the impregnation portions 10 and 11 corresponding to
the gasket forming portions in the gas diffusion layers 5 and 6 so
as to face to the separators 8 and 9, and the gaskets 15 and 16 are
respectively bonded to the impregnation portions 10 and 11 by an
adhesive agent or the like. The groove-like gasket receiving
portions 17 and 18 are formed in the separators 8 and 9 so as to
correspond to the gaskets 15 and 16. The electrolyte membrane 2 is
set smaller in size than the size of the gas diffusion layers 5 and
6, however, may have the size equal to the size of the gas
diffusers 5 and 6.
Eleventh Embodiment
[0119] FIG. 11 shows an embodiment in which a silicon rubber is
impregnated in the gasket material impregnation portion of the gas
diffusion layer, as a first embodiment of a single part of the gas
diffusion layer. That is, the silicon rubber is impregnated in the
gasket forming portion in the gas diffusion layer 5, whereby the
impregnation portion 10 is formed.
Twelfth Embodiment
[0120] FIG. 12 shows an embodiment in which a silicon rubber
impregnating process in the gasket material impregnation portion of
the gas diffusion layer and the silicon rubber insulating spacer
forming process are integrally carried out, as a second embodiment
of the single part of the gas diffusion layer. That is, the
insulating spacer 12 made of the same silicon rubber is integrally
formed on one surface of the impregnation portion 10, as well as
the silicon rubber is impregnated in the gasket forming portion in
the gas diffusion layer 5, whereby the impregnation portion 10 is
formed.
Thirteenth Embodiment
[0121] FIG. 13 shows an embodiment in which a silicon rubber
impregnating process in the gasket material impregnation portion of
the gas diffusion layer, the silicon rubber gasket forming process
and the silicon rubber insulating spacer forming process are
integrally carried out, as a third embodiment of the single part of
the gas diffusion layer. That is, the insulating spacer 12 made of
the same silicon rubber is integrally formed on one surface of the
impregnation portion 10, and the gasket 15 made of the same silicon
rubber is integrally formed on an opposite surface of the
impregnation portion 10, as well as the silicon rubber is
impregnated in the gasket forming portion in the gas diffusion
layer 5, whereby the impregnation portion 10 is formed.
Fourteenth Embodiment
[0122] FIG. 14(A) shows an embodiment in which the gaskets 15 and
16 are formed after increasing a bulk density by compressing the
gasket forming portion of the gas diffusion layer 5, as a fourth
embodiment of the single part of the gas diffusion layer, and FIG.
14(B) shows an embodiment in which the bulk density is increased by
compressing the gasket forming portion of the gas diffusion layer
5, and the silicon rubber impregnating process in the gasket
material impregnation portion 10 and the silicon rubber gaskets 15
and 16 forming process are integrally carried out. That is, in FIG.
14(B), the gaskets 15 and 16 respectively made of the silicon
rubber are integrally formed on both surfaces of the impregnation
portion 10, respectively, as well as the silicon rubber is
impregnated in the gasket forming portion in the gas diffusion
layer 5, whereby the impregnation portion 10 is formed.
Fifteenth Embodiment
[0123] Next, a description will be given of one embodiment of a
method of manufacturing the fuel cell. The method is as
follows.
[0124] That is, first, as shown in FIG. 15, in accordance with the
same manner as the twelfth embodiment mentioned above, the gas
diffusion layer 5 is formed by integrally carrying out the gasket
material impregnating process in the gasket material impregnation
portion 10 of the gas diffusion layer 5, and the gasket material
insulating spacer 12 forming process, and next, as shown in FIG.
16, the UEA 7 is formed by integrally bonding the gas diffusion
layers 5 and 6 to both surfaces of the membrane electrode complex
1. Next, as shown in FIG. 17, the desired number of through holes
14 and 15 and manifolds are formed so as to extend through, and
next, as shown in FIG. 18, the gaskets 15 and 16 are formed, and
next, as shown in FIG. 19, the stack is assembled by arranging the
separators 8 and 9. FIG. 20 shows a cross sectional view including
a gas introduction portion (a gas communication groove) 62 for
supplying a reaction gas within a separator surface, in the cell
stack in FIG. 19 which is assembled in accordance with the
manufacturing method mentioned above. Since the gasket material
impregnation portion 10 of the gas diffusion layer 5 is opposed to
the gas communication groove 62, the spacer 63 which is
conventionally required is unnecessary. Further, since it is not
necessary to arrange the gasket in the gasket material impregnation
portion 10 of the gas diffusion layer 5 opposing to the gas
communication groove 62, the through hole is not provided.
EFFECT OF THE INVENTION AND INDUSTRIAL APPLICABILITY
[0125] The present invention achieves the following effect.
[0126] That is, first, in accordance with the fuel cell on the
basis of the first aspect of the present invention provided with
the structure mentioned above, it is possible to prevent the
separator and the UEA from being broken due to the fastening after
stacking, owing to the structure and the operation mentioned above.
Further, it is possible to uniformly apply the fastening pressure
to all of the gaskets, it is possible to securely obtain good seal,
and it is possible to secure a safety as well as an improvement of
a power generating efficiency. Further, it is possible to reduce a
manufacturing cost of the gasket. Further, in a stacking step of
alternately stacking the separator and the UEA, the work can be
easily carried out and can be automated. Accordingly, it is
possible to reduce a cost for manufacturing the stack. Further,
even in the case that disassembly of the stack is required, the
work can be easily carried out without breaking the structure
material such as the separator, the gasket, the UEA and the like,
so that it is possible to reuse and repair the structure material.
Further, it is possible to obtain a good seal performance without
relation to the thickness of the UEA in the gasket forming
portion.
[0127] Further, in accordance with the fuel cell on the basis of
the second aspect of the present invention provided with the
structure mentioned above, since it is possible to easily form the
gasket, the insulating spacer and the gasket material impregnation
portion owing to the structure and the operation mentioned above,
it is possible to reduce the cost for manufacturing the stack.
Further, it is possible to easily arrange the insulating spacer in
the gas diffusion layer. Further, it is possible to apply a uniform
fastening force to all of the gaskets, it is possible to securely
obtain a good seal, and a safety can be secured as well as an
improvement of a power generating efficiency. Further, in the
stacking step of alternately stacking the separator and the UEA,
the work can be carried out simple and can be automated.
Accordingly, it is possible to reduce the cost for manufacturing
the stack. Further, even in the case that disassembly is required
in the stack, it is possible to easily carry out the work without
breaking the construction material such as the separator, the
gasket, the UEA and the like, so that it is possible to reuse and
repair the structure material.
[0128] Further, in accordance with the fuel cell on the basis of
the third aspect of the present invention provided with the
structure mentioned above, it is possible to prevent the separator
and the UEA from being broken due to the fastening after stacking,
owing to the structure and the operation mentioned above. Further,
it is possible to apply a uniform fastening force to all of the
gaskets, it is possible to securely obtain a good seal, and a
safety can be secured as well as an improvement of a power
generating efficiency. Further, it is possible to reduce the cost
for manufacturing the gasket. Further, since it is possible to
securely prevent the reaction gas from leaking from the end portion
of the gas diffusion layer, the interface between the gas diffusion
layer and the insulating spacer, or the interface between the
insulating spacers, it is possible to improve the safety.
[0129] Further, in accordance with the fuel cell on the basis of
the fourth aspect of the present invention provided with the
structure mentioned above, it is possible to prevent the separator
and the UEA from being broken due to the fastening after stacking,
owing to the structure and the operation mentioned above. Further,
it is possible to apply a uniform fastening force to all of the
gaskets, it is possible to securely obtain a good seal, and a
safety can be secured as well as an improvement of a power
generating efficiency. Further, it is possible to reduce the cost
for manufacturing the gasket. Further, in the stacking step of
alternately stacking the separator and the UEA, the work can be
carried out simply and can be automated. Accordingly, it is
possible to reduce the cost for manufacturing the stack. Further,
even in the case that is required in the stack, it is possible to
easily carry out the work without breaking the construction
material such as the separator, the gasket, the UEA and the like,
so that it is possible to reuse and repair the structure
material.
[0130] Further, in accordance with the manufacturing method on the
basis of the fifth aspect of the present invention provided with
the structure mentioned above, in the stacking step of alternately
stacking the separator and the UEA, the work can be carried out
simply and can be automated, owing to the structure and the
operation mentioned above. Accordingly, it is possible to reduce
the cost for manufacturing the stack. Further, even in the case
that is required in the stack, it is possible to easily carry out
the work without breaking the construction material such as the
separator, the gasket, the UEA and the like, so that it is possible
to reuse and repair the structure material.
[0131] Further, in accordance with the manufacturing method on the
basis of the sixth aspect of the present invention provided with
the structure mentioned above, in addition to the same effects as
those of the third or fourth aspect mentioned above, the following
effects can be obtained, owing to the structure and the operation
mentioned above. That is, in the stacking step of alternately
stacking the separator and the UEA, the work can be carried out
simply and can be automated. Accordingly, it is possible to reduce
the cost for manufacturing the stack. Further, even in the case
that is required in the stack, it is possible to easily carry out
the work without breaking the construction material such as the
separator, the gasket, the UEA and the like, so that it is possible
to reuse and repair the structure material. Further, it is possible
to widely reduce the manufacturing cost at a time of mass
production.
[0132] Further, in accordance with the manufacturing method on the
basis of the seventh aspect of the present invention provided with
the structure mentioned above, the same effects as those of the
sixth aspect mentioned above can be obtained by using the adhesive
rubber material, owing to the structure and the operation mentioned
above.
[0133] Further, in accordance with the manufacturing method on the
basis of the eighth aspect of the present invention provided with
the structure mentioned above, the same effects as those of the
sixth aspect mentioned above can be obtained by securing the
surface roughness of the gas diffusion layer and forming the gasket
thereon.
[0134] Further, in accordance with the fuel cell on the basis of
the ninth aspect of the present invention provided with the
structure mentioned above, in addition to the same effects as those
of the first to fourth aspect mentioned above, the following
effects can be obtained, owing to the structure and the operation
mentioned above. That is, it is possible to easily form the gasket
in the gas diffusion layer and it is possible to reduce the
manufacturing cost. Further, it is possible to prevent the reaction
gas from leaking from the end portion of the gas diffusion layer,
and the safety can be secured as well as the improvement of the
power generating efficiency.
[0135] Further, in accordance with the fuel cell on the basis of
the tenth aspect of the present invention provided with the
structure mentioned above, in addition to the same effects as those
of the first to fourth aspect mentioned above, the following
effects can be obtained, owing to the structure and the operation
mentioned above. That is, it is possible to easily form the gasket
in the gas diffusion layer and it is possible to reduce the
manufacturing cost. Further, it is possible to prevent the reaction
gas from leaking from the end portion of the gas diffusion layer,
and the safety can be secured as well as the improvement of the
power generating efficiency. Further, it is possible to fix the
gasket to the gas diffusion layer without applying the adhesive
agent to the gasket forming portion.
[0136] Further, in accordance with the fuel cell on the basis of
the eleventh aspect of the present invention provided with the
structure mentioned above, in addition to the same effects as those
of the first to fourth aspect mentioned above, the following
effects can be obtained, owing to the structure and the operation
mentioned above. That is, in addition that it is possible to obtain
a high gas seal performance against the gasket leak from the end
portion of the gas diffusion layer, it is possible to obtain a high
gas seal performance against the leak in the interface between the
gas diffusion layer and the separator, so that the safety can be
secured as well as the improvement of the power generating
efficiency. Further, it is possible to prevent the gas diffusion
layers from shorting between an anode pole and a cathode pole, at a
time when the through holes are provided after integrating the UEA.
Further, it is possible to prevent a compressive buckling of the
end portion of the gas diffusion layer due to the stack
fastening.
[0137] Further, in accordance with the gas diffusion layer on the
basis of the twelfth aspect of the present invention provided with
the structure mentioned above, in addition to the same effects as
those of the first to fourth aspect mentioned above, the following
effects can be obtained, owing to the structure and the operation
mentioned above. That is, it is possible to prevent the gas
diffusion layers from shorting between an anode pole and a cathode
pole, at a time when the through holes are provided after
integrating the UEA. Further, it is possible to prevent a
compressive buckling of the end portion of the gas diffusion layer
due to the stack fastening. Further, it is possible to reduce the
cost for manufacturing the UEA. Further, errors in integrally
bonding is reduced, and it is possible to improve a yield
ratio.
[0138] Further, in accordance with the gas diffusion layer on the
basis of the thirteenth aspect of the present invention provided
with the structure mentioned above, the same effects as those of
the first to fourth aspect mentioned above can be obtained, owing
to the structure and the operation mentioned above.
[0139] Further, in accordance with the manufacturing method on the
basis of the fourteenth aspect of the present invention provided
with the structure mentioned above, in addition to the same effects
as those of the first to fourth aspect mentioned above, it is
possible to reduce the cost for manufacturing the UEA, owing to the
structure and the operation mentioned above.
[0140] Further, in accordance with the fuel cell on the basis of
the fifteenth aspect of the present invention provided with the
structure mentioned above, the same effects as those of the first
to fourth aspect mentioned above can be obtained, owing to the
structure and the operation mentioned above.
[0141] Further, in accordance with the fuel cell on the basis of
the sixteenth aspect of the present invention provided with the
structure mentioned above, in addition to the same effects as those
of the first to fourth aspect mentioned above, the following
effects can be obtained, owing to the structure and the operation
mentioned above. That is, since the specific positioning jig is not
required at a time of alternately stacking the UEA and the
separator, and it is possible to easily stack, it is possible to
reduce the cost for manufacturing the stack. Further, it is
possible to achieve a high seal performance, and the safety can be
secured as well as the improvement of the power generating
efficiency. Further, it is possible to prevent the UEA and the
separator from being broken in the end portion due to a buckling
deformation at a time of fastening the stack body.
[0142] Further, in accordance with the fuel cell on the basis of
the seventeenth aspect of the present invention provided with the
structure mentioned above, in addition to the same effects as those
of the first to fourth aspect mentioned above, it is possible to
reduce the cost for manufacturing the UEA, owing to the structure
and the operation mentioned above.
* * * * *